The long-term goals of this project are to gather information which will aid in the prevention of atherosclerosis, principally through biochemical analysis of in vitro cell culture systems. The human diploid fibroblast cell culture system is being used to study the regulation of lipid biosynthesis and degradation. Cells derived from normal individuals and hypercholesterolemic individuals are being investigated with respect to LDL suppression of sterol biosynthesis LDL binding, sterol binding, and uptake.